18617939 has 2 divisors, whose sum is σ = 18617940. Its totient is φ = 18617938.

The previous prime is 18617933. The next prime is 18617947. The reversal of 18617939 is 93971681.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18617939 - 2⁴ = 18617923 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 18617939.

It is not a weakly prime, because it can be changed into another prime (18617933) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9308969 + 9308970.

It is an arithmetic number, because the mean of its divisors is an integer number (9308970).

Almost surely, 2^18617939 is an apocalyptic number.

18617939 is a deficient number, since it is larger than the sum of its proper divisors (1).

18617939 is an equidigital number, since it uses as much as digits as its factorization.

18617939 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 81648, while the sum is 44.

The square root of 18617939 is about 4314.8509823631. The cubic root of 18617939 is about 265.0394577534.

The spelling of 18617939 in words is "eighteen million, six hundred seventeen thousand, nine hundred thirty-nine".